I suppose it had to happen. Apple was rumoured to be launching a 'slate' computer so others including HP have done so too.

All of which leaves me a bit bemused. You see, I don't really know what these slate computers are for.

Let's be straightforward. The first touch-sensitive laptops came out while I was on the staff of a computer magazine, and I've been freelance since 1993 so I can date it pretty precisely. It's a long time ago. They were some use in data capture but never really set the world alight.

This was mostly because nobody ever developed a killer application for them. Microsoft OneNote was as close as it got.

Then HP developed a desktop touch-sensitive PC which it touted as the kitchen computer a couple of years ago. Again, it didn't deliver the sales because nobody really, if they were honest, knew what it was for.

Now we have Apple and others lining up to launch these things. Yes, there are games, yes, there are eBooks which are better designed for this sort of device than they were before. But seriously, before anyone launches another of these things, can someone show me a killer app that tells me why anyone might want one?